public static function initPrioSwitch()
 {
     global $REX;
     // include main class
     if (!class_exists('rex_prio_switch')) {
         include $REX['INCLUDE_PATH'] . '/addons/website_manager/classes/class.rex_prio_switch.inc.php';
     }
     // include extended class for use in this addon
     include $REX['INCLUDE_PATH'] . '/addons/website_manager/classes/class.rex_website_manager_prio_switch.inc.php';
     // for ajax call: update prio in db if necessary
     rex_website_manager_prio_switch::handleAjaxCall('website_manager', 'update_websites_prio', 'rex_website', 'id', false);
 }